*Each year around £2.5bn could be being spent on advertising that is ending up on pornographic, illegal or abusive sites

All of which should create a market for Project Sunblock of course, which claims it remove such ad placings automatically. The findings are hardly surprising in a world in which more and more online ads are going through ad exchanges and the like; clever wheezes to remove all human influence on the business of buying and placing media.

If advertisers really are worried about this – as opposed to paying lip service to it – there is another quite simple solution: get a human. But that would cost more, of course.